Blast furnace distributor control



June 22, 1943- .A. J. WHITCOMB ETAL 2,322,406

BLAST FURNACE DISTRIBUTOR CONTROL 6 Sheets-61m l,

Filed Jan.v 7.. 1941 Fi I IzurJ.

on-Fo' v v 'Ari q June 22, 19430 A, J, WHITC'OMB ETAL. 2,322,406 BLASTFURNACE DISTRIBUTOR CONTROL Filed Jan. 7, 1941, 6 Sheets-Sheet 2Arifhurlwizia y z Gard 12 F0 June 22, 19 3- I A. J. 'wHiTc oMB ETAL 6BLAST FURNACE DISTRIBUTOR CONTROL Filed Jan. 7, 1941 6 Sheets-Sheet 3INVENTOR Arthur J. Whiicomb Fox Gardon By %%M June 22, 1943. Q 'B ETAL2,322,406

BLAST FURNACE DISTRIBUTOR CONTROL Filed Jan. 7, 1941 s Sheets-Sheet 4 0fix. J ,2w 1 Wm- Tn Rm Z a a m 3 m M m w q mm Mm won um MW Wm 0 a. s 7am C mmnm Rm 7 S S 2 2 hBm 5 M, m a D a c v E m w I -m Am 1 I I m Tu 1 CC M 56666 66% mu: 3 M A H H 3 4 6 5 9R 1 U u 1 MMWQQ U n r. r. n. u 3 3U l n uuwbwm EWLNQLM mz ut fiuuwbnm Lukas: at

' INVENTOR. Arthur J Wh ifcomb GogdanFoxf ATTO BY.

June 22, 1943. A. J. WHITCOMB ETAL 2,322,406

BLAST FURNACE DISTRIBUTOR CONTROL Filed Jan. 7, 1941 6 Sheets-Sheet 6 8NmT J In QNN - INVENTOR. G d Wji zjfcomb 01" 021 OK 7 7MX4ORN Y.

Arth ur J. y 2J1 Patented June 22, 1943 BLAST FURNACE 2,322,406 7DISTRIBUTOR CONTROL Arthur J. Whitcomb and Gordon Fox, Chicago,

Engineering Co 111., assignors to Freyn Chicago, 111., a corporation ofMaine Application January 7, 1941, semi No. 313,441?

16 Claims. (01. 214-37) The present invention relates to improvements inblast furnace distributor controls.

It is desirable in charging a blast furnace to distribute the materialsin such a way as to avoid vertical channels therein. Blast. furnaces ascommonly constructed are charged from a skip hoist, two skips beingordinarily provided, which deliver material alternately into a singledischarge conduit, delivering into the distributor hopper at the top ofthe furnace. The discharge conduit commonly takes the form of anelliptical cone terminating in an approximately circular outlet, the twoskips commonly dis charging into said conduit adjacent to the ends ofthe elliptical contour of said conical conduit. The skip outlet has afixed position relative to the furnace, and inasmuch as the outlet fromthe conduit discharges downwardly and laterally of the distributorhopper at the top of the furnace, the net effect is that the largerlumps of material are thrown toward that side of the hopper spaced fromthe skip discharge and the finer material drops more or less verticallytoward that side of the hopper adjacent to the skip discharge. Due tothe fact that the two skips have their discharging positions disposedadjacent to the two ends of the elliptical contour of the conicaldischarge conduit, there is a tendency for one of said skips to throwthe larger lumps of the material discharged therefrom in a directiondisposed angularly with respect to the direction of throw of the largerlumps from according to a prearranged plan in successive layers of saidother types of material.

A further object is to provide distributor con-' trol mechanism forinsuring the size distribution above referred to independently ofdifferences in the number of skip discharges which comprise a cycle or aportion of a cycle.

A further object is to provide control mechanism for controlling therotation of the distribthe other of said skips. Generally speaking, the

effect of the discharges from the skips is to throw the larger lumps ofmaterial toward the a far side of the hopper and to allow the finerparticles to drop to the inner side of the hopper.

An object of the present invention is to provide mechanism .forcontrolling the distributor hopper at the top of a blast furnace wherebythe size distribution of the material charged into the furnace may beeiiectlvely controlled,

A further object is to provide control mechanlsm for the distributorhopper of a blast furnace whereby size distribution of the materialcharged into the furnace may be controlled automatically according to apredetermined plan to avoid vertical channeling.

A further object is to provide distributor control mechanism forinsuring that the larger lumps of any particular type of materialcharged of the other types of material will be distributed utor inrelation to the dumps of the large bell, to the end that thedistribution of the coarse material and the fine material in any layermay be according to a preferred plan.

A further object isto provide improved distributor mechanism forinsuring the desired size distribution of any type of material chargedinto the furnace regardless of the ratio of the number of dumps of thesmall bell per dump of the large bell.

A further object is to provide control mechanism for insuring that thecoarse lumps and the smaller particles of any material charged into thefurnace are symmetrically distributed about the axis of the furnace in agenerally helical arrangement.

A further object is to provide a control mechanism in which the changesof angularity of movement of the distributor are had in response to thedischarges of the large bell rather than in response to anypredetermined number of discharges of the small bell.

A further object is to provide a control mechanism in which suitabledistribution of the material can be assured by relatively simple means.

A further object is to provide a control mechanism for a blast furnacecharging system in which operation of the distributor hopper and theskip hoist mechanism may be carried out simultaneously without dangerthat said skip hoist mechanism will reach discharging positions beforesaid hopper is in condition to receive material therefrom.

A further object is to provide distributor control mechanism forimproving the performance of a blast furnace.

A further object is toprovide distributor control mechanism well adaptedto meet the needs of commercial. operation.

Further objects will appear as the description proceeds.

Referring to the drawings- Figure 1 is a diagrammatic view of a blastfurnace installation embodying the principles of the present invention;

Figure 2 isa wiring diagram of a distributor control mechanism which maybeused-in connectlmwiththedisclosureofl 'igure l:r'igureflisadiagrammaticviewofmeansfor providing a atepy-step movementof an angle program switch in response to dumps of the large bell of ablast furnace;

Figure4isawiringdiagramshowingamodification of the circuits shown inFigure 2;

Figure 5 illustrates another modification; and

Figure illustrates a further modification particularly applicable to thediagram, illustrated in Figure 4.

'Referring first to Figure l, a blast furnace is indicated by thenumeral ll. At the top of this furnace are .the small hell it and thelarge bell i2 arranged in series with one another. Said small bell ii iscontrolled by means of the lever I I, which in turn is controlled by thecable. I adapted to be operated by the small bell operating cylinder II.The large bell I2 is adapted to be controlled by the lever ll, adaptedto be controlled by the cable II, which is connected to be operated bythe large bell cylinder I8. As shown, the small bell cylinder it when inits lowermost position holds the small bell H in closed position.Likewise the large bell cylinder. it when in its lowermost positionholds the large bell l2 in its closed position. Associated with thesmall bell cylinder I 0 is the limit switch SBT, which is biased to openposition and is closed when the small bell operating cylinder I is inits uppermost position, that is when the small bell II' is fully open.Associated with the large bell operating cylinder II i the limit switchLBT. which is biased to open position, and is closed when the large belloperating cylinder i8 is in its uppermost position, that is--when thelarge bell i2 is fully open.

Connected to rotate with the small bell I I is the hopper It. A motor 20is connected to the hopper I 9 .for communicating a rotative movement tosaid hopper l9 and small bell it. One of the two skip tubs of a skiphoist is indicated by the numeral 2|. Said skip tubs dmnp into the chute2| a for discharging downwardly and laterally into the hopper l8.

Adapted to be driven by the hopper I9 is the hopper limit switch 22.According to the control diagram, which will be described presently, thehopper limit switch 22 is adapted to make a complete rotation of 360while the hopper I 0 rotates through an angle of 60.

The numeral 23 indicates a control panel, the circuits of which may bein accord with the diagrams shown in Figures 2, 4, 5 or 6. The numeral24 indicates an angle program switch, and

thematerialsmaybechargedintothefurnace inthefollowingmanner:Onea'kip'loadofore-and twoskiploadsofcokemaybedepoaitedintothehopper,thesmallbellbeingopenedafterthedeposit of each skipload thereon.As indicated above, inasmuch as the discharge from the skip ill thenumeral 25 indicates a distributor program switch. The angle programswitch 24 is adapted to be driven by the motor 20, and the distributorprogram switch is adapted to be driven by the motor 21. The connectionsbetween the control panel 23, angle program switch 24, distributorprogram switch 20, hopper limit switch 22, the small bell limit switchSBT and the large bell limit switch L'BT will be clear from thediscussion of the control diagram (Figs. 2, 4, 5 and 6) which discussionwill appear presently.

Before proceeding vwith a discussion of the control diagrams, a typicalsequence of' discharges of material into the blast furnace may bediscussed. As indicated above, the present invention has'for one ofits'principal objects the control of the size distribution of each typeof material discharged from the large bell into the furnace.

hoist is from one side of the blast furnace, the distribution ofmaterial is broadly such that the larger-lumps go to that side of thehopper distant from the discharge outlet of the skip'and the finerparticles drop to that side of the hopper adjacent to the skip. Afterthe one skip of ore and the two skips of coke have been deposited in thehopper and in turn have been discharged upon the large bell, the largebell is dumped, communicating the irregular distribution of the largerlumps to one side of the furnace and the finer particles to the otherside of the furnace.

Proceeding with the example given above, one

skip of ore followed by one skip of stone followed by two skips of cokemay be discharged into the hopper. After each of these skiploads, thehopper is rotated 60' and the small bell is then g gfined, dischargingthe material onto the large In every instance the large particlesdischarged from the skip predominate in the region of the hopper distantfrom the skip incline and the finer particles predominate in the regionadjacent to the skip incline.

Since each of the skiploads in the second group was rotated 60 byrotation of the hopper, which rotates as a unit with the small bell, theposition of the materials in this group is at a position 60 from theposition of the materials in the first group. When the large bell isdumped to deposit these four skips of ore, stone and coke into thefurnace the deposition of the coarse lumps and liner particles isangularly displaced, with respect to the deposition of the correspondinglumps of the first group, through an angle of 60.

The next operation is to discharge one skipload of ore and two skiploadsof coke in succession into the hopper. After each deposit into thehopper, the hopper with the small bell is rotated and is discharged ontothe large bell. After these three skips have been deposited the largebell is opened to discharge the material into the furnace. Thearrangement of large lumps and small lumps in this third layer ofmaterial with in the furnace is displaced angularly with respect to thefirst group or layer, an amount equal to 120, and with respect to thesecond group or layer an amount equal to 60 The next deposits of oneskip or ore, one skip of stone and two skips of coke in the next groupare carried to the position. The deposits in the next group whichcomprise one skip of ore and two skips of coke are carried to the 240position with respect to the centerline of furnace. The next depositscomprising one skip of ore, one skip of stone .and two skips or coke arecarried to the 300 60 position, the coarse coke of the next coke is thatthe rotation of the hopper and the small bell is controlled in relationto the dumps of the large bell, so that the distribution of the coarseand fine lumps of any material may be symmetrical; that is to say, thedesired symmetrical distribution of the coke, for example, is hadregardless of the ratio of the number of dumps of the small bell 'perdump of the large bell. In other words, the coarse lumps and the finesof any material are symmetricallyarranged about the vertical axis of thefurnace in a distribution which may be termed "generally helical. The

nated patent, the large bell may Open once after a group comprising onenumber of skiploads, three for instance, and may again discharge after adiffering number of skiploads, four for instance. when the distributoris made to respond to the discharge of the large bell it also respondsto the .variations in the numbers of skiploads which constitutesuccessive groups, such variation being a significant element of PatentNo. 1,937,951. Because of the fact that changes of the angle rotation ofthe hopper are thus completely kept in a synchronized or symmetricalrelationship with the discharges of the large bell, instead of beingunrelated thereto, the distribution described in this disclosure may betermed a symmetrical distribution as contrasted with the ran- I domdistribution which may result from previous changes of ,angularity inthe distribution of material onto the large bell and into the furnaceoccur in response to the discharges of the large bell and not inresponse to any predetermined I number of discharges of the small bell.

In previous practice, in controlling the charg- 'ing of blast furnaces,it has been the practice to provide a means to count the discharges ofthe small bell and to cause the large bell to operate in response to aselected number of such discharges. (Fox et al. Patent No. 1,937,951.)It has also been known to provide separate mechanism to count thedischarges of the small bell and to cause the distributor control tooperate to change angularity in response to a selected number of suchdischarges. (Harwood Patents Nos. 1,801,502 and 1,888,501.)

It should be noted with reference to the previously known typicaloperation that if the angle of rotation were changed after each fourskips and consequent four discharges of the small bell, the followinggrouping would result:

oup 1 One ore, two cokes, one ore.

Group 2 One stone, two cokes, one ore.

Group 3 Two cokes, one ore, one stone.

. Group 4 Two cokes, one ore, one coke.

Group 5 I One coke, one ore, one stone, one coke.

Group 6 No. 1,937,951), and the distributor control which is made torespond directly to the large bell may 'thus indirectly respond to thesingle counting means instead of two separate countingmeans. Moreover,as was indicated in the above desig-' definite increments prescribed bythe angle propractice.

A description of the control diagram of Figure 2 may be prefaced by ashort discussion of the hopper limit switch. the angle program switchand the distributor program switch above referred to.

In general, the hopper limit switch measures the movement of thedistributor hopper in definite increments (60 increments in theembodiment illustrated) and insures that said hopper will be stoppedonly at the end of one of these increments of movement.

The angle program switch operates in response to the dumping operationsof the large bell. vIt selects and prescribed the number of 60increments which comprise each movement of the distributor hopper forone group of small bell discharges constituting one charge upon thelarge bell. The number of definite increments thus prescribed is changedto each dumping operation of the large. hell, or multiple thereof.

The function of the angle program switch disclosed in Figure 5 issimilar to that immediately above discussed, except that in thedisclosure in Figure 5 the extent of movement of the distributor hopperis determined by allowing prescribed time intervals for said movement.

The distributor program switch operates in response to the movements ofthe distributor hopper. In general it functions to execute the ordersprescribed by the angle program switch. It counts the number of 60increments of movement traversed by the distributor hopper, and incombination with the hopper switch, it causes the movement of thedistributor hopper to cease after said hopper has traversed the numberof gram switch. The distributor program switch is disclosed only in themodification shown in Figure 2. Its function is accomplished throughother means in the modifications illustrated in Figures 4, 5 and 6.

In the system illustrated in Figure 2, several relays are used, whichmay be described as follows:

The letters AP indicate the operating coil of a relay having theswitches AP (biased to closed position), AP and AP (both biased to openposition). While coil AP is energized switch AP is open and switches APand AP are closed.

The letter F indicates the operating coil of a relay having the switchI, biased to open position. Energization of the coil F closes switch FThe letter X indicates the operating coil of a relay having theswitchesX (biased to open position) and X (biased to open position). While thecoil X is energized, switches X and X are closed.

TheletterYindicstestheoperatingcoiloi arelayhsvingtheswitchesYHhissedtoopenposition) and .Y":(biased to open'pcsitionL- *While the coilYis energised-switches Y and'! are Theletters DP indicate the operating coil oi a relay having the switches DPand DP (both biased to open position). While coil DP is energised,switches DP and D! are closed.

The letter M indicates the operating coil of a relay having the switchesw and so (both biased to open position While coil M is energized,

to close the switch 1', which is in shimting relationship with theswitch AP".

The coil it above mentioned is adapted to be connected across thecircuit 28-28 by the switch AP'providedtheangleprogramswitchisinapredetermined position.

The'coil 1'', above mentioned, which controls the switch l" 01' thehopper drive motor 28 is adapted to be connected across the circuit28-28 by the switch SR provided the angle program switch 28 and thedistributor program switch 28 are in relay having the switches 83 and BB(both biased to open position). While coil SB is energized, switches SBand SB are closed.

In Flgureii the numerals 28-28 indicate the two sides of an electriccircuit. Connected across the circuit 28-28 is the hopper drive motor 28having armature and series field windings. The connection of the motor2'8 to the circuit 28 is controlled by the switch I, which switch isresponsive to the coil F adapted to be connected across the circuit28-28 through certain switches controlled by the angle program switch 28and the distributor program switch 25, to be described presently.

The series motor 28, which drives the angle program switch 28 is alsoadapted to be'connected across the circuit 28-28. The connection oi saidmotor 28 to the circuit 28-28 is controlled by the switch AP (biased toclosed position) and by the switch X (biased to open position). Inshunting relationship with the switch X is the switch Y. Said switches Xand Y are controlled by the coils X and Y, respectively,

which are responsive to positions of the angle program switch 28, to bedescribed presently.

The motor 21 for driving the distributor program switch 25 is also aseries motor. The connection of the motor 21 across the circuit 28-28 iscontrolled by three switches in parallel with one another, to wit-theswitch M the switch N and the switch S13 The switch M is responsive tothe coil M, the switch N is responsive to the coil N, and the switch SEis responsive to the coil SB. The coils M, N and SB are all responsiveto the positions of the program dis tributor switch 28. J

The characters AP indicate a coil whose connection to the circuit 28-28is responsive to the large bell limit switch LBT, which, as statedabove, is adapted to be closed only when the large bell is in its fullyopen position. The coil AP controls three switches, as follows: AP,which is biased to closed position and controls the circuit of the motor28, as above described; the switch AP; and the switch AP. The switchesAP and AP are biased to open position. The switch AP is in circuit withthe coil X, above mentioned, and when closed is adapted to connect saidcoil X across the circuit 28-28, provided the angle program switch 28 isin a predetermined position. The 0011 X, in addition to operating theswitch x as above mentioned, is also adapted predetermined positions.Said switch SR is responsive to the coil BR, which coil SR is adapted tobe connected across the circuit 28-28 when the limit switch L8 or thelimit switch R8 is closed, provided the distributor program switch 28 isin a predetermined position.

The limit switches LS and'RS are closed while the left or the right skiptub, respectively, is in the skip pit, which means that the other skiptub is in discharging position. The coil 1'' is also responsive to thehopper limit switch 22, in a manner to be described presently.

The coil 83 is adapted to be connected across the circuit 28-28 uponclosure of the limit switch SBT, which, as noted above, is closed whenthe small bell is fully open. Such action occurs, however, only when thedistributor program switch 28 is in a predetermined position. Said coilSB, when energized, will close the switch SB and the switch SB. Saidswitch 8B is in short-circuiting relationship with the limit switch SBT.

is the pair of contacts '28. In circuit with the switch AP and the coilY is the pair of contacts 88. In circuit with the switch SR and the coilF are five parallel circuits, 01 which one circuit includes the pair ofcontacts 8! and the pair 01' contacts 82; another circuit includes thepair ct contacts 88 and the pair oi contacts 88; another circuitincludes the pair of contacts 88 and the pair of contacts 88; anothercircuit includes the pair of contacts 81 and the pair oi contacts 88;and the fifth circuit includes the pair of contacts 88 and the pair ofcontacts 88.

In circuit with the coil M are the switch DP and a pair of contacts 8i.Bridging the switch D1 i the switch 1W, which switch M is biased to openposition but is closed when the coil M is energized.

In circuit with the coil N are the switch DP and the pair of contacts82. Bridging the switch DP is the switch N". Said switch N is biased toopen position but is closed when the coil N is energized. The switchesDP and DP are biased to open position but are closed when the coil DP isenergized. In the circuit of the coil SR are the limit switches LS andRS, above referred to, which limit switches are in parallel and arealternatively closed when one or the other 01' the two skip tubs is inthe skip pit. In this same circuit are the pair of contacts 88. Saidpairs of con tact 28, 88, 8|, 88, 88, 81 and 88 are adapted to bebridged selectably in response to the positions of the angle programswitch 28. The pairs of contacts", 88, 88, 88, 88, 8|, 82, 88 and 88 areadapted tobe bridged in response to positions 01 the distributor programswitch 28.

The numeral 88 indicates a pair of contacts adapted to connect the coilF across the circuit 28-28. Said contacts 88 are adapted to be bridgedin response to positions of the hopper limit switch 22. The coil DP isadapted to be connected across the circuit 28-28 through the In thecircuit oi the switch s1" and the cos x aaaasoo pair of, contacts 40,which contacts are adapted to be bridged when the hopper limit switch22- is in a predetermined position.

The six positions 01' the angle program switch 24 are indicated by thenumerals 1, 2, 3, 4, and 6, and contact members are illustratedinconnection with thesix positions referred to for selectably-bridgingthe pairs of contacts 22,30, 3|, 33, 35, 31 and 33. Switches foraccomplishing this purpose are available to those skilled in the art andneed not be described in detail. It may be stated briefly that the pairof contacts 23 are bridged when the angle program switch 24 is inposition 1, 3 or 5. The pair or contacts III are bridged when the angleprogram switch 24 i 'in position 2, 4 or 6. The pair of contacts 3| arebridged when the angle program switch 24 is in position 2, 3, 4, 5 or 6.The contacts 33 are bridged when the angle program switch 24 is inposition 3, 4,5 or 6. The contacts 35 are bridged when the angle'programswitch 24 is in position 4, 5 or 6. Contacts 31 are bridged when theangle program switch 24 is in position 5 or 6,

and the contacts 33 are bridged when the angle the pairs 01. contacts32, 34, 35, 3B, 40, 4|, 42, 43

and 44 under predetermined selected conditions. The contacts 32 arebridged when the distributor program switch 25 is in position 1. Thecontacts 34 are bridged when the distributor switch is in position 2.Contacts 38 are bridged when the distributor switch 25 is in position?Contacts 33 are bridged when the distributor program switch 25 is inposition 4, and the contacts 40 are bridged when the distributor programswitch 25 is in position 5. Contacts 4| are bridged when the distributorprogram switch 25 is in position 1, 3 or 5. Contacts 42 are bridged whenthe distributor program switch 25 is in position 2, 4 or 6. Contacts 43are bridged whenthe distributor program switch 25 is in position 1, andcontacts 44 are bridged when the distributor program switch 25 is inposition 2, 3, 4, 5 or 6.

Contacts 45 are bridged when the hopper limit spaced angularly from thezero position,

to wit: between60 and 120; between 120 and 180; between 180 and 240;between 240 and 300; and between 300 and 360. Contacts 45 are adapted tobe bridged when the hopper limit switch 22 is in the following positionspaced angularly from zero position, to wit: between 60 and 120. I

The mode of operation of the circuits illustrated in Figures 1 and 2 issubstantially. as follows: When the large ball I2 i fully open, thelimit switch LBT is closed. Closure of the limit switch LBT results inthe energization oi the coil AP, resultingnn the closing of the normallyopen switches AP and APP, andalso resulting in the opening of thenormally closed switch AP Under these conditions the angle programswitch 24 is in its first position, thereby bridging the con- .runsuntil the circuit of the coil X is opened,

which opening'will occur when the angle program switch 24 has moved toposition 2. In this one position each time the large bell is opened.

when one oi. the skip tubs reaches the skip pit, that is-the end of itstravel, one oi. the

limit switches L8 or R8 is closed, thereby energizing the coil SR,resulting in the closure 0! the switch SR Switch SR remains closed whileeither of the skip tubs is in the skip pit, during which interval theentire cycle of operation or the distributor hopp r. I! occurs. Closureof the switch SR sets up a group of circuits associated with the angleprogram switch 24 and with the distributor program switch 25. Since theangle program switch 24 is now in position 2 and the distributor programswitch 25 is in position 1, a circuit is established between theconductors 23-28 through the switch SR contacts 2|, con

tests 32 and the coil F. Energization or the coil F "causes the closingoi the switch I", causing the hopperdrive motor 20 to operate, therebyrotating the hopper. Discontinuance or this rotation is governed by thedistributor program switch 25 and the hopper limit switch 22, as will bediscussed presently. f

When the hopper limit 'switch 22 rotates through an angle of 60, thatis-10 rotation of the hopper, the contacts 45 are bridged, therebyestablishing a maintaining circuit for the coil F, insuring that thehopper l3 will. continue to rotate at least through one increment oi!60". that is, 360 oi the hopper limit switch 22.

The bridging of the contacts 46 by the hopper limit switch 22establishes a circuit of brief duration through'the coil DP, resultingin the closure 01' the switches DP and DP. Closure of the switchDPestablishes a circuit through the coil M, since contacts 4| are bridgedby reason of the fact that the distributor program switch 25 is inposition 1.. Energization of the coilM results in the closure of switchM2, establishing a maintaining circuit for the coil M. Energization ofcoil M also results in the closure of the switch M causing the motor 21to operate the program switch 25. The motor 21 continues to operateuntil the circuit of coil M is interrupted by the advancing of thedistributor program switch 25 to position 2, in which position thecontacts 4| are unbridged.

When the distributor program switch 25 advances to position 2, thecircuit of coil F through the contacts 32 is interrupted, resulting inthe opening of the switch F The motor 20 driving the hopper l3 willtherefore stop after-the hopper has made one increment (60) of rotation,corresponding to 360 rotation of the hopper limit switch 22, causing theparallel maintaining circuit of coil F to be interrupted at the contacts45, as previously described.

It will be remembered that the angle program switch 24 advances oneposition each time that the large. bell I2 is dumped. If the angle pro-1 gram switch 24 were in position 3, two circuits would be completed tothe coil F, to wit through the contacts 3| and the contacts 32, andthrough contacts- 33 and contacts 34. The first mentioned circuit, thatis-through contacts 3| and contacts 32, is completed only when thedistributor program switch 25 is in. position l. The other of these twoparallel circuits, that 'skip tubs being in the pit) while thedistributor program switch 25 is in its positions 1 and 2.

Therefore the hopper II will be revolved through two 60' incrementsinvolving two revolutions of the hopper limit switch".

It should be noted that coil 1'' can be energized through two routes.One route involves the contact ll, 55, 35, 51 or a and the contact 22,

revolved exactly a 60 increment. Hopper limit switch 22 insures that thehopper drive motor 20, once started, travels through 60 increments andstops only at the end of such increments, which is to say-only when thehopper limit switch 22 is in its zero position. The related positions ofthe angle program switch 24 and the distributor program switch 25determine how many 60 increments the hopper I 5 will travel before itstops.

It should be noted that there is no provision to energize the coil Fwhen the angle program switch is in its position 1. Consequently thehopper I! is not rotated under these conditions and the hopper limitswitch 22 remains in its zero position. This position 1 of the angleprogram switch 24 corresponds to the zero angle position of the hopperl5. When the angle program switch 24 is in position 2, the hopperrotates one increment of 60"; when the angle program switch 24 is inposition 3, the hopper it rotates through two increments of 60 each,making a total fl20' before stoppin when the angle program switch 24 isin position 4,. the hopper it rotates three increments of 60",

making a total of 180 before it stops; when the angle program switch 24is in position 5, the hopper it rotates through four increments of 60,equalling 240', before stopping; when the angle program switch 24 is inposition 6, the hopper it rotates throughflve increments of 60, totaling300' before it stops.

It was iniitally assumed that the distributor program switch 25 startedfromposition 1. In counting the increments of rotation of each hopperload of material, the counting according to this description isinitiated from the same starting .position, that is-with the distributorprogram switch 25 in its position 1. The distributor program switch 25is rotated to position 1 after each skipload in the hopper I! has beenproperly rotated. This rotation of the distributor program switch 25 canbe accomplished in various ways. One way is as follows:

The small bell II is discharged after each skipload is depositedthereon, such discharge taking place after the designated rotation ofthe hopper I! has been completed. Operation of the small bell ll maytherefore be used to initiate the action which causes the distributorprogram switch 25 to return to its position 1 prior to discharge of eachskipload of material from the hopper I5. If the distributor programswitch 25 is in any of its positions 2, 3, 4, 5 or 6 when the small bellll reaches its full open position, closure of the small bell limitswitch SBT completes a circuit through the coil SB, contacts 44 beingbridged at this time. Energization of the coil SB results in the closureor the switch $.33.

asaaaoo establishing a maintaining circuit for itself until thedistributor program switch 25 reaches its.

now be a step by step movement through connections with the large belloperating cylinder. Secured to the large bell operating cylinder II isthe counterweighted chain 41 trained over the sheave 48. Said sheave isattached to the shaft I! having the bearing 50. Said shaft 40 carriesthe pawl 5| adapted to cooperate with the. ratchet wheel 52. Secured tothe ratchet wheel 52 is the shaft 53 adapted to operate the angleprogram switch ll.

While Figure 2 shows a combination in whichthe angle program switch ismotor driven, and a distributor program switch,also motor driven. is

employed in connection with the hopper switch. Figure 4 shows amodification for accomplishing the same result as obtained in thecombination disclosed in Figure 2. .However, in the combina-' tion ofFigure 4 the angle program switch is mechanically driven by the largebell mechanism. In the combination of Figure 4 the distributor programswitch is omitted, and the angle program switch functions in connectionwith a modiiied hopper switch to perform the functions requiring thethree special switches in the combination of Figure 2. I

Referring now to Figure 4, the numeral 55 indicates a hopper. switch,which, similarly to the hopper switch 22 of Figure 2, is driven from thedistributing hopper It. The system disclosed in Figure 4 involvesseveral relays which may be described as follows:

The letters DT indicate the operating coil of a mined time interval toclose the switches DT and DT and open the switch DT.

The letters DM indicatethe. coil of a relay having the switches DM and.Did (both biased to open position) and the switch 13M (biased to closedposition) While the coil DM is energized the switches DM and DM will beheld closed and the switch DM will be held open.

The letters SBR-Cand SBR-T indicate, respectively, the closing coil andthe trip coilof a latched relay, which coils control the switch SBR(biased to closed position). When coil SBRC is energized, switch SBR.will be opened and latched open. Energization of the trip coil SBR-Twill unlatch said switch 8131?. and allow it to return to its closedposition.

tion), When the coil A is energized it .will latch position.

'hell ll.

Theletterhindicatestheclosingeoiloia havingtheswitch B'(biasedtoopenpositionY and the switch BF (biased to closed position).

When' energised the coil is latches the switch a in closed position andthe 'switch 13 in open The letter C indicates'the closing coil of alatched relay having the switch C (biased to open position) and theswitch C (biased to closed position). When the coil C is energized theswitch Cl is latched in closed position and the switch C is latched inopen position.

The letter D indicates the operating coil 01' a relay having the switchD (biased to open position) and the switch D (biased to closedposition).When the coil D is energized the switch.

I) is latched in closed position and the switch 13' is latched in openposition.

The letter it indicates the closing coil of a relay having the switch I!(biased to closed position). when the coil E is energized it latchestheswitch it in open position.

. The letters AT, BT, CT, 171'! and ET indicate trip coils for therelays of coils A, B, C, D and E, respectively. 7 v

The numerals 58, 59, 50, ii, 02 and 53 indicate pairs of contactsadapted to be bridged selectively when the angle program switch It is inpredeterminer positions. 'It may be explained briefly that contacts 58are bridged when the angle program switch 54 is in zero position;contacts 59 are bridged when said angle program switch is in the 60position; contacts 50 are bridged when said angle program switch is inthe 120 position; contacts 6| are bridged when the angle grogram switchis in the 180 position; contacts 62 are bridged when said angle programswitch is in the 240 position; and contacts 63 are bridged when saidangle program switch is in the 300 position.

by one or the other of the two limit switches LB and R8 is a coil havingthe reference letters BBB-C for opening the switch SBR circuit with thecoil BBB-C is the normally closed switch DT'.

The letters PB indicate a switch which for convenience may be termed a,push button switch Said switch when closed will inaugurate certainoperations which will continue even though the switch is opened at once.adapted to bridge the pair of contacts ll-ll and the pair of contactsIi-|l.- When the contacts ll-II are bridged it will inaugurate theoperation' of control mechanism for the large bell l2.

Instrumentalities foraccomplishing thisresult are known to those skilledin the art and need not be described'herein. It is suillcient to statethat instrumentalities suitable for the purpose are described andclaimed in the Whitcomb Pat-- ent No, 1,928,039 and in the Fox andWhitcomb Patent No. 1,937,951. The letters 88 indicate the operatingcoil of a relay having the switch SS biased to open position when theswitch PB is moved to bridge contacts ll-H. This action causes theenergizationoi the operating coil SS.

A, B, C, D and E, respectively. Said trip coils are connected across theconductors -55 through the small bell limit switch SBO, which is biasedto open position but is closed when the small bell II is open.

The numerals 54, 65, 6 6, 51, 58 and 69 indicate pairs of contactsadapted to be bridged when the hopper switch is in predeterminedpositions. It may be explained briefly that contacts 54 are bridged whenthe hopper switch 55 is in any position except its zero position;contacts 65 are bridged when said hopper switch is in the 300' position;contacts 56 are bridged when said hopper switch is in the 240 position.The letters LBC indicate a limit switch for the large bell l2. Saidlimit switch LBC is biased to closed position but is open vwhile thelarge bell is open. The letters SBO indicate a limit switch for thesmall Said limit switch S30 is biased to open position but is closedwhile the small bell is open. The numerals 56-55 indicate the two sidesof an electric circuit, across which is a circuit including the armatureand series field winding of the hopper drive motor 51, which may beconnected to the hopper I! in a manner similar to that illustrated inFigure 1. In the circuit of the motor 5'! is the starting resistance Rbridged by the normally open switch Z In series with the motor 51 in thecircuit across the conductors 50-55 is the normally open switch DM Thereference letters IS and RS indicate limitswitches controlled by theskip tubs of the skip hoist (not illustrated). When either the left-handskip tub or the right-hand skiptub is in the pit, one of these limitswitches will be closed. The letters DI indicate a coil controlled thenormally closed switch S8. Also controlled In discussing the operationof the control system illustrated in Figure 4, it may be assumed thatboth the angle program switch 54 and the hopper switch 55 are in theirzero positions.

When either the left-hand or the right-hand skip tub enters the skip pitand theother skip tub reaches its upper limit of travel, the limitswitch LS or RS will be closed. This causes the coil DT to be energized..As noted above,

the relay which includes the coil DT is a time delay relay whichfunctions only after a time interval suflicient to permit the materialto be discharged from the skip tub into the hopper l9. After the lapseof the predetermined time interval the coil DI' operates to close theswitches D1 and UT and to open the switch D'I. Closure of the limitswitch LS or R8 also results inthe energization of the coil SBR-C,resulting in the opening of the switch SBR preventing starting of. theskip hoist and also preventing functioning of the small bell Ii. Afterthe lapse of the predetermined time interval, switch DT will close,completing a circuit for the coil SBR-T, causing the opening of theswitch SBR eration of the small bell ii and/or the skip hoist. It may benoted in this connection that it will be preferred to connect the switch813R. in the same manner as a push button, whereby :only momentaryclosure is necessary to start operations, holding circuits then beingestablished to cause the cycle to be completed. Such holding circuitsneed not be illustrated herein inasmuch as circuits suitable for thepurpose are well Said switch PB 18- This condition .permits opthe art.Asuitable circuitisillustratedinthecoilBS andtheswitch -When the-angleprogramis. iii its m position it is not desired that the hoppergramswitch uisinitssei-opositiouitis ose sible for-the small bell tobeoperated and for the skip hoist to be operated after each discharge ofa skipload-into the small bell hopper.

After a predetermined number of skiploads have been discharged into thehopper it and have been furtherdischarged by thesmall bell I i withoutrotation of the hopper, it willbe desirable to lower the large bell I!to discharge the material into the furnace. It will be further desirableto change the arrangement so that any additional skiploads will berotated through the proper angle before the small bell Ii is opened. Letit be assumed that three skiploads have been discharged into the hopperl and in turn have been discharged onto the large bell I! with zerorotation. .When the fourth' skipload is being hoisted the push button PBis depressed, thereby energizing the coil 88, closing the switch S8 andopening'the switch 88. As noted above, the energization of the coil 88is maintained as long as the'switch LBC is closed by reason of theclosure of the switch 88 Inasmuch as switch as: has been opened, the

time delay relay having the coilDT cannot function. The effect is asfollows: When the fourth skipload (iirst skipload or the new series)reaches asaasoe Whcnthe hopper I. M torotate, it'll)-Hperswitchllalsostartstorotatethishopper Thus when the angleproswitchbeing mechanically connected to thehoppertomakeacompleterevolution fol-cachet) of rotation of the hoppers".When the hopper switch I has moved 00' (10 of Mormonment), a circuit iscompleted through the hopper switch I] and contacts 04 to energizethecoil DM.

this circuit being in parallel with the circuit through'the angleprogram switch 04, contacts ll and the normally closed switch A. Whenthe hopper switch ll has rotated 300' (50' of hopper movement), acircuit is completed through the the top of the furnace, the closingcoil BBB-C is energised, causing the switch 8BR to open.

The trip coil SBR-T cannot be energized until the switch U1 is closed,and switch Ul cannot close as long as the sequence switch 88' is open.Therefore the switch 813R remains open, preventing the lowering of thesmall hell I i or the further starting of the skip hoist until switchSB'isclosed.

The'operation or the switch PB will also in augurate operation of thelarge bell control, as above referred to. When the large bell reachesits full open position, limit switch'LBC opens,

thereby interrupting the circuit of switch 58 inswitch 04 from the zeroposition to the 60 podtion. When the time delay relay having the coil171 had operated to close the switch DI, it at closing coil A. Thiscauses closure or the switch A and causes the normally closed switchA'to open. When the normally closed swith A opens, one circuit for thecoil DM is interrupted; However, the parallel cireuit through thecontacts 00 is maintained" through the coil DM until the hopper switchhasf traveled to its zero When this has happenedthe coil DM is deenergized and the distributor stops.

When the switch DMZ opens the switch DIP clom,'thereby permitting-thetripcoil EBB-T 'tobeenergized. Thisinturncauses the closure of theswitch 8BR, permitting the small bell H to be lowered and the skip hoistto be operated.

After a desired number of skiploads have been discharged into the hopper[I and have each been rotated 60' from zero position before discharge,it will again become desirable to dump the large bell l2. Again thebutton PB is depressed. The large bell i: is dumped. and the anglepropram switch It is advanced to its third position, to wit-the 120position. When the angle program switch I4 is in its 120' position itsets up a circuit through the normally closed switch B. When in duecourse the distributor hopper it rotates and its hopper switch It.

reaches the 300 position of said hopper switch, the contacts I arebridged. energizing the coil A, closing the switch A and opening theswitch A. There is no immediate result when the normally closed switch Ais opened, because the circuit involved is already 'open at anotherpoint. However, closure of the switch A sets up a circuit through theclosing coil B. This circuit does not become efi'ective until the hopperswitch II has the same time caused the closure of the switch DT'.Therefore when the angle program switch advanced to its 60 position,this caused the circuit to be completed through the normally closedswitch A, through coil DM, thereby closing the switch DM and opening theswitch DML This made it impossible to energize the trip coil BBRe-T.Since it is thus impossible to close the contacts SBR the small bell ilcannot be discharged and the skip hoist cannot again be started whilethe switch DME is open, that is made one complete rotation through 360and an additional rotation through 240. When this happens the circuitfor the closing coil B is completed, causing clomlre of the normallyopen switch B and opening of the normally closed switch B' As a resultof this action the distributor hopper I! is caused to stop as soon asthe hopper switch I! has reached its zero position. Thus the hopperswitch has been turned through two revolutions, giving movement or thedistributor hopper ll. Y

In like manner the distributor hopper. is caused to rotate throughthree, four or live increments of 60 each when the angle program switch'4 is in its 240' or 300 position, respectively.

It should be noted that switch A moves in unison with switch A. thatswitch B moves in unison with switch B, that switch C moves in unisonwith switch C, and that switch D moves in unison with switch D'QSwitches A, B, C and D are moved to closing position by means of theclosing coil A, B, C or D, respectively, and are latched in said closingpositions. Switch E is also a latched switch, and switches A, B, C, Dand E. are all released from latched position by means of the trip coilsAT, BT, CI. 171 and ET.

while the distributor hopper I! is in movement. 75 respectively. It willbe noted that the trip coils assasoe AT, 8'1. '1. DI and II. are ,incircuit with the small bell limit switch 880. which is biased toposition. being closed only when the small h in its extreme openposition. Since the opened after each discharge into the oppor, any orall of the switches A B (I and D A, 8', C, l) and E are returned totheir positions when the small bell is dumped.

It should be noted that the trip coil BBB-T obtains itlgrcuit throughthe angle program switch 54 when that switch is in its zero position.when that switch is not in zero position it is necessary that the tripcoil sBlt-T be energized through a diflerent circuit. This circuitis-completed when the switch A is closed, indicating that thedistributor hopper it has initiated its rotation. The circuit throughcoil SBRv-T is closed. however. only after switch DM' closes, when motor51 completesthe increment of rotation. It will be recalled that theswitch BBB. is a permissive relay which permits the small hell I i andthe skip hoist to be started. Thus it will be noted that this permissionis not given until the distributcrhopper I! is properly positioned.

In the above discussion reference has been made to the switch PB as apush button switch. This reference i for purposes of convenience only.In many actual installations the equivalent result will be obtainedthrough automatic means associated with the counting mechanism operatedby the small bell, so that after the small bell has made a desirednumber oi. discharges, a contact oi short duration is made, equivalentto the action or a push button. Structures equivalent to smash buttonare well known to those skilled in the art.

the hopper II is driven by the motor 51 having the armature and seriesfield windings as in Figure 4. The circuit of said motor is controlledby the switch DM Also in circuit is the resistance R adapted to becutout by the switch Z. Figure 5 the two limit switches LB and R8 areconnected in parallel toeontrol the circuit of the coil DT and thenormally-closed switch 882, as well as the circuit including the closingcoil vSBlt-C! and the normally closed switch D'I", as

in Figure 4. The trip coil 8BR.-T is connected across the circuit 12-12through the normally open switch NT which is responsive to the coil NT,to be described presently.

The angle programswitch 13 may be moved with a ratcheting movementsimilar to that disclosed in Figure 3, being moved an increment of 60for each cycle of movement of the large bell operating cylinder.

Cooperating with the angle program switch 13 are a plurality of pairs offlxed contacts, indicated by the numerals 14, 15, 16, 11, 18 and 18.

' It will be sumcient to state that the contacts 14 For example, thestart button 41L appearing in Figure 2 of the Fox and Whitcomb PatentNo. 1.937 ,951, has a function corresponding to the elementPBin Figure 4oi the present application.

the large bell. In other words, rotation of the hopper I! cannot beinitiated until and unless the large bell has been discharged and inconnection therewith has advanced the angle program switch 54 throughthe next increment of rotation. This is an important point, as itprevents improper inclusion of the first skipload in a new series withthe skiploads of the previous series.

Proceeding now to a description of the alternative electrical diagramshown in Figure 5, many of the instrumentalities disclosed in Figure 5are also disclosed in Figure 4. In the system disclosed in Figure 5 thetime delay relay having the operating coil DT also includes the switch171" (biased to open position), as well as the switches UT" and D1. Inthe system illustrated in Figure 5 the relay which includes theoperating coil DM, though 'it also includes the switches DM and DM, hasno switch corresponding to the switch DM or Figure 4. In the system ofFigure 5 the relay having the operating coil NT also includes theswitches NT and NT (both biased to open position) and the switch N'I(biased to closed position).

The two sides of the electrical circuit disclosed in Figure 5 areindicated by the numerals 12-12. According to the system disclosed in we5,

are bridged when the angle program switch 13 isv in any one oi theangular positions 80, I20. I80, 240, 300, but is unbridged when saidangle program switch is in its zero position. The contacts 15 arebridged when the angle program switch 13 is in its zero position or its60 position. The contacts 10 are bridged when the angle program switchis in its 120 position. The contacts 11 are bridged when'the angleprogram switch is in its |lii position. The contacts 18 are bridged whenthe angle program switch is in its 240 position, and the contacts 19 arebridged when the angle program switch is in its 300 position.

In circuit across the conductors 12-12 are the contacts 14, theoperating coil DM, the switch DE, and the switch 8BR, or which thelatteris biased to open position and is responsive to the closing coilSBR--C and t0 the trip coil SBR-T. Bridged across the circuit whichincludes the coil DM, switch DI and switch SBlt is a circuit includingthe switch DM and the operating coil Z.

Figure 5 illustrates a combination similar to that illustrated in Figure4 except that the hopper limit switch is replaced by a time delaydevice.

According to the system disclosed in Figure 5, a time delay device isprovided for giving. the hopper is time to rotate after each dischargeof the skip tub. The particular time delay relay chosen for illustrationis a Nee-timer involving a condenser, adjustable resistances, adischarge tube, and certain relays. Such Nee-timer relays are known tothose skilled in the art and have been described in the May 1939 issueof the Iron and Steel Engineer, pages 62 to 71, particular referencebeing had to page 68. Forcooperation with such a switch, the variableresistance R is provided in circuit with the contacts 15,

ll. In bridging relationship with the tube II is the switch NT (biasedto open position).

Referring to the functions of the system disclosed in Figure 5, it maybe assumed that the angle program switch It is in its zero position.When either the left-hand or the right-hand skip tub reaches its upperlimit of travel the limit switch L8 or R8 will be closed. Closure ofeither limit switch LB or R8 results in the energization of the coilSBRP-C, it being remembered that the normally closed switch 171" isclosed during the time interval before the operating coil DT functions.Therefore the normally closed contacts 813R. open, preventing furtherstarting of the skip hoist and also preventing functioning of the smallbell. Simultaneouslythe contacts 8BR close. Closure of the limit switchLB or R8 also causes the coilDT to be energized. As noted above, thiscoil DT is the operating coil of a time-delay relay, which functionsonly after a time interval sumcient to permit the material to bedischarged from a skip tub into the hopper II. This time-delay relayfunctions to close the normally open contacts UT and 171' and to openthe normally closed contacts 171".

When the switch 17! closes, this is a step toward operation of theNeo-timer operating coil NT. In due course, as. later explained, thiscoil NT functions to close the switches NT and NT and to open switchNT", all for a short period of time only. Closure of the switch NTcompletes a circuit for the trip coil SBR-T, whereby switch 8BR. closes.Since switch BBR is closed, the skip hoist and the small bell H can beoperated.

It may be noted that, as previously stated, the switch D'I was openedwhen the relay of the coil DT functioned. Hence the closing coil BBB-Cwas deenergized, making it possible for the trip coil BER-T to function,as described in the preceding paragraph.

Thus, when the angle program switch II is in its zero position it ispossible for the small bell II and the skip hoist to be operated aftereach discharge into the small bell hopper (after a suitable delay fordumping). There is no rotation of the hopper because the-circuit of thecoil DM is open at the zero position of the angle program switch I3.

The function is slightly difierent when the angle program switch It isin its 60 position (caused by operation of the large bell operating.

cylinder). When the limit switch L8 or R8 closes, the relays having thecoils SBR-C and DT function as above described. Closure of the switchesDC! and SBR' now completes a circuit for the coil DM. Closure of theswitch DM causes energization of the motor I!- to rotate the hopper l9.Closure of the switch DM energizes the coil Z, closing the switch 2,which short-circuits the accelerating resistor R after a slight delay,since the coil Z and switch Z form part of a time-delay contactor.

The previously mentioned closure of the switches SBR' and DT impressed avoltage upon the condenser ll through the adjustable resistor R When thevoltage on the condenser reaches the break-down voltage of the dischargetube ll, the condenser 80 discharges through the tube and the coil NT.Th flow of current through the coil NT causes it to close its switchesNT and NT and to open its switch NT. Closure of the switch NT closes adischarge circuit for the' condenser around the tube It. The relaycomprising the coil NT and the switches NT, NT

and NT will remain in this position only mementarily until thecondenservoltage reduces to the drop-cut voltage thereof when the relay returnsto its original position.

As indicated above. the function of the Neotimer involving the condenserII and the tube ti is to introduce a definite time interval for rotationof the hopper it. As the speed at which the hopper it rotates issubstantially constant. the angle of rotation is closely dependent uponthe time of rotation. The time for the condenser to'charge and build upits voltage to the voltage of the break-down tube ii is dependent uponthe resistance of the resistor R Adjustment of this resistor controlsthis time period. When indue course the switch NT is closed. the tripcoil BBB-T is energized. This leads to the opening of the switch 8BR.This causes stopping of the hopper drive motor II by interrupting thecircuit of the coil DM.

When the trip coil BBR-T is energized the switch 8BR closes. Thiscondition permits the skip hoist and the small bell II to be againstarted. It is thus seen that after a skip tub reaches the top of itstravel and after a dumping time introduced by the relay of the coil 171,the distributor hopper II is started into rotation. This rotationcontinues for a definite time, determined by the Nee-timer. and sincerotation is substantially constant, the hopper rotates through acorresponding angle, and at the end of the time. as determined by theNee-timer, rotation is discontinued and the switch BBRds reset to permitthe discharging of the small bell ii and further starting of the skiphoist mechanism. This cycle is repeated until it is desired to dischargethe large bell l2. Movement of the large bell cylinder It to effect thedischarging of the large bell results in the ratcheting forward of theangle rogram switch is b mechanism such as shown in Figure 3.

To elect the opening of the large bell, the push button PB may bedepressed while the skip mechanism is in transit and while the lastskipload of a series is being discharged from the small bell. When thisbutton P8 is depressed. coil 88 energized to rotate the hopper II.

is energized. causing switch 88 to close and causing switch S8 to open.Opening of the switch 58 interrupts the circuit of the coil 17! so thatthe relay coil DT cannot function. Therefore, when either of the skiptubs of the skip mechanism reaches its limit of travel, switch 8131i. isopened, so that the small bell cannot be discharged and the skipmechanism cannot be started. Also because the switches I71" and 171" areopen, the hopper drive motor ll cannot be Whm the large bell it opensand thereby opens the limit switch LBC, the coil 58 is deenergined,switch 88' closes, the coil U1 is energized and may function, and thecycle may proceed. Thus the proper allocation of the operations of thelarge hell with respect to the skiploads of material deposited thereonis assured.

When the angle program switch I! is in its hopper II are had when theangle program switch is in its 180"position, the 240 position and the300 position, the corresponding resistors R, R

, operation of the distributor hopper I .is concerned. Certain changeshave been introduced. principally with reference to'the timing of thevariousevents. 'In the structure of Figured a certain amount of time issaved by reason of the iact that the skip hoist mechanism is permittedto start when the distributor hopper has made a partial movement. Inother words, the initiation of movement of the skip hoist mechanism isnot delayed until .the distributor hopper finishes its movement. Thepoint in the hopper movement at which the skip hoist mechanism ispermitted tostart depends upon the total hopper move-. ment required.

The description of the system illustrated in Figure 6 may be prefaced bythe explanation that in the operation of charging a blast furnace, aload of material is loaded into a skip tub at the skip pit. The skip tubis then raised to the top of the furnace, and upon arriving at the topof the fumace the skip tub is tilted, causing the I contents to bedischarged into the hopper above ,the small bell. The hopper includingthe smallbell is then rotated through an angle which may be zero, 60,120, 180, 240 or 300, as described in connection with the precedingfigures. After the hopper has completed the necessary amount of rotationthe small bell is caused to open, is held open for a desired pauseperiod, and then closed. The next succeeding skipload of material maythen be discharged into the hopper above the small bell. I

It should be noted that three actions are involved in sequence, to wit:(a) material is discharged from a skip tub into the distributor hopper;(b) the distributor hopper is revolved through the desired angle; and(c) the small bell is opened, held open, and closed. Each of theoperations referred to involves a corresponding time period. To insurethat all materials will be discharged from the skip tub, a timeallowance is introduced by means of the time delay relay involving thecoil D'I', as previously described. This relay is commonly set tointroduce a time interval in the order of seconds. The time required forthe rotation of the distributor hopper varies somewhat in individualcases, but is commonly of the magnitude of 4 seconds for each 80 ofrotation. The time required to open and close the small bell is alsosubject to variation, but is frequently of the magnitude of 8 seconds toopen, 4 seconds to pause and 8 seconds to close.

making a total for this operation of 8 plus 4 plus 8, equaling seconds.

Obviously the skip hoist cannot be started while a skip tub thereof isbeing held at the'top of the provided the companion skip tub hasreceived its charge of materials in the skippit. Ordinarily the timerequiredto load material into one skip tub at the skip pit approximatesthe 10-second interval necessary to insure discharge of material timethat the distributor hopper is being rotated and while the small bell issubsequently being \small bell is open, it is essential that therotationopened and closed. As it is not desirable that the skip tubdischarge into the distributor hopper while the hopper is in rotation orwhile the of the hopper and the subsequent movement of the small bell becompleted before the ascending skip tub starts to discharge. Whether ornot this condition'exists depends upon the relative times of thesimultaneous movements. I! movement'of the skip hoist is so fast thatthe ascendmg skip tub reaches the top of the furnace in less time thanis required for the necessary distribu tor and small bell movement, thenthere would be a tendency for the skip to discharge into the distributorhopper while the small bell is'still open. I

" In order to avoid such a contingency the skip hoist control of theblast furnace is commonly before askip tub ascends to the dischargeposifurnace to insure that all materials are discharged therefrom.Therefore it is impossible either to start the skip hoist; to revolvethe distributor hopper, or to open-the small bell during the period ofapproximately 10 seconds allocated to the discharge of materials from askip tub into the distributor hopper. It is physically feasible,

however, for the skip hoist to start its movement as soon as thematerials have been discharged,

tion, various steps can be taken. For instance the movement of the skipcan be made so slow that under anycircumstances the top movement will becompleted within the time required for the skip trip. In some controlsthe initiation of the skip movement is delayed until after thedistributor hopper has completed its rotation. Then the only top actionthat must occur during the skip trip is the opening and clos ng of thesmall bell. This can always be done in less time than is required forthe skip trip. Neither of the above expedieots is entirely satisfactory,as they both involve a considerable degree of slowing down of thecharging operation.

The system illustrated in Figure 6 involve; in practice the delaying ofthe i'nitiationof movement of the skip hoist under special cond tionswhere such delay is essential, avoiding such delaying of the skip hoistin all instances where such delay is not essential.

Typ'callyi, a complete trip from the lowermost position of 'a sk p-tubto the final dumping position may be said to require about 40 seconds.Of this interval about 7 seconds are required for capsizing the skip tubat the top of the incline. Thus about 33 seconds are required forascension of the skip tub to the point where capsizing is initiated. Aspreviously stated, the rotation of the distributor hopper requires about4 seconds per 60 increment, and the complete opening and closing of thesmall bell requires about 20 seconds. Thus it will be noted that if thedistribu- 12 tor hopper is rotated through the time necessary for suchrotation and for opening and closing of the small bell is 4 seconds plusseconds, equal to 24 seconds. Under these circumstances it is obviousthat it a skip tub starts to tor hopper, the small bell will be closedarter 28- seconds, a satisfactory situation. When the distributor hoppermust revolve through 180', the smallbellwillbeclosedarterlzsecondsplusnseconds, equal to 32 seconds. and a skip tub willstarttocapsiseaiter33seconds. Thisistooclose aracetoinsuredeiinitelythatthesmallbellwfll be closed beiore discharge or material starts. Whenthe hopper must rotate 240' the time required for such rotation is 18seconds, so that the small bell will not be closed in a period shorterthan 16 seconds plus 20 seconds, equal to 36 seconds. Inasmuch as theascending skip tub starts to capsize after 33 seconds, it is obviousthat the discharge of materials will be initiated before the small bellis closed.

The system or control illustrated in Figure 6 is such that when theangle program switch is in such position as to cause rotation of thedistributor hopper through zero, 60' or 120. operation of the skip hoistis permitted to be initiated simultaneously with the initiation ofrotation of the distributor hopper. However, when the angle programswitch is in position to cause 180 rotation oi the hopper, movement orthe skip hoist is delayed in order to give the hopper a handicap. Whenthe angle program switch is in position to cause 240' rotation of thehopper, movement or the skip hoist is similarly handicapped, but to agreater degree. When 300' rotation of the distributor hopper is calledfor, the hopper is given a still greater handicap and the movement ofthe skip is delayed to a greater extent.

mthesystemillustratedinFigureiLanangle program switch is indicated bythe numeral 84. The coil SBR-C controls a switch SBR', biased to closedposition, which diflers from the switch SBR of Figure 4 in that theswitch BBB is permissive only with respect to operation of the smallbell. In parallel relationship with the coil SBR-C is the coil SKR-C,which controls the switch SKR biased to closed position. Said switch SKRispermissive with respect to the skip hoist mechanism. Expressed inother language, the switch SBR permits initiation oi the opening andclosing movements oi the small bell and the switch SKI-t permitsinitiation of movements oi the skip hoist mechanism.

The letters SKRT indicate a trip coil for the switch SKR Said trip coilBKRr--T1S adapted to be energized when either of the skip tubs is at thetop of its travel (which results in the closure of the switch LS or theswitch RS) provided the angle program switch is in predeterminedpositions and provided the switch DTI i in closed position.

The numerals l5, I6, 81 and 83 indicate, respectively, pairs of contactsadapted to be bridged when the angle program switch 34 is inpredetermined positions. It will be sufllcient to state that thecontacts ll are adapted to be bridged when the angle program switch isin its zero, 60 or 120 position. The contacts 88 are adapted to bebridged when the angle program switch 34 is asaasoe 7 in its 180position. The contacts 01 are adapted to be bridged when the angleprogram switch I is in its 240 position, and the contacts II are adaptedto be bridged when the angle program switch is in its 300 position. Inbridging relationship with the contacts II is a circuit including thecontacts ll and the switch A, which is biased to open position and iscontrolled by the coil A, being closed when the coil A is energised.Also in bridging relationship with the contacts II is the circuitincluding the contacts .1 and the switch B, which is biased to openposition but is closed when the coil B is energized. Also disposed inbridging relationship with the contacts II is the circuit including thecontacts I. and the switch C biased to open position. Said switch 0' isclosed when the coil C is energized.

Figure 6 shows an alternative arrangement of the trip coils AT, BT, CT,D'I'I and ET, said trip coils being arranged in parallel relationshipwith one another instead of being arranged in series relationship withone another as shown in Figure 4. Either arrangement is satisfactory.

If the angle Program switch 34 is in the acre, 60 or position, the tripcoil BER-T is energized as soon as the time delay relay involving theswitch D'I' has operated. When said relay operates, the switch D'I'closes. Energizetion of the trip coil SKR-T allows the switch SKR'. toclose, thereby permitting initiation oi movement of the skip hoistmechanism. If the angle program switch 84 is in its 180 position, thetrip coil SKR-T is not energized when the timing relay involving theswitch DI' closes, and therefore the skip hoist is not permitted tostart at the same time that the hopper is started. When the hopper hasrevolved through an angle of 50, corresponding to 300 movement of thehopper limit switch I, the contacts 6! are bridged, energizing theoperating coil A, thereby closing the switch A. Circuit is therebycompleted from one side of the circuit II-II through either of the limitswitches L8 or R8 through the contacts ll, switch A, trip coil SKRT andswitch DT to the other side oi said circuit. Energization of the tripcoil SKR-T restores switch SKl't to its closed position, therebyterminating the prohibition introduced when energization of the coilSKR-C had opened the switch SKR Initiation of movement of the skip hoistis thereby permitted. Thus it will be seen that movement of the skiphoist is delayed until the distributor hopper has traversed about 50 ofits rotation. There remain about of rotation of the distributor hopper.This would require about 8.7 seconds, which added to the 20 secondsrequired for the opening and closing movements of the small bell makes atotal or 28.7 seconds, which is safely within the 32 seconds requiredfor ascension of the skip tub.

Similarly, when the angle program switch 84 is in the 240position,.permission for the skip hoist to start is not given until thehopper limit switch is in the 240 position, at which point the contacts06 are bridged and the coil 8 is energized, resulting in the closure ofthe switch B, which completes a circuit through one of the limitswitches L8 or R8, through contacts l'l, switch 13 trip coil SKR-T, andthe switch m to the other conductor 12. This position of the hopperlimit switch II is reached when -the hopper has traveled through 100 ofits total of 240 of movement. Similarly, when the angle program switch84 is in its 300 position the skip hoist is not permitted to start untilafter the fifim 7 related to the dump of the large bell for de-"distributor hopper has made 60 plus 60 plus 30, ualing 150' of its totalof 300 of movement.

With the means disclosed in Figure 6, movement of the skip hoist isdelayed only when the angle program switch 84 is in certain positions,and then the delay is only of sufllcient magnitude to insure that thesmall bell will be closed for a reasonable interval before the ascendingskip tub reaches the capsizing position. This delay is introduced intothe cycle only under certain conditions where such delay is essential,and the delay is minimized to the extent necessary.

It should benoted in Figure 3 that ratchet wheel 82 is mounted directlyon the shaft which is driven from the large bell. Moreover, it drivesdirectly angle program switch i4.v By interposing a 2:1 gear reductionbetween wheel 52 and switch It, the amplitude of rotation of the lattercan be reduced so that two movements of the large bell are necessary toadvance the angle program switch 60. With this arrangement the change ofamplitude of rotation of the hopper can be made to occur not with everydump of the large bell but with every other dump of the large bell. 'Insome instances the resulting distribution, still symmetrical and helicalin character, is thought to be more advantageous. The claims should beconstrued with reference to arrangements wherein the change of amplitudeof hopper rotation responds either directly to the dumps of the largebell or to multiples thereof.

Though certain preferred embodiments of the present invention have beendescribed in detail, many modifications will occur to those skilled inthe art. It is intended to cover all such modifications that fall withinthe scope of the appended claims.

What is claimed is:

1. In combination, a blast furnace having a small bell, a rotarydistributor hopper associated with said small bell, a large bell inseries with said small bell, and control means for governing theamplitude of the angular rotation of said distributor hopper in responseto dumping operations of said large bell.

2. In combination, a blast furnace having a small bell, a large bell inseries with said small bell, a rotary distributor hopper cooperatingwith said small bell, which hopper is adapted to receive material from aside thereof, and means for progressively varying the angular movementsof said distributor hopper in response to dumps of said large bell.

3. The method of controlling the distributions of a plurality of typesof materials in a blast furnace which materials are delivered inincrements in a regular sequence to form groups, which groups areintroduced into the furnace in regularly repeated order, which materialsare delivered at the top of said furnace with the coarser portion ofeach increment angularly disposed with relation to the finer portionthereof, which consists in rotating the positions of the coarser portionof any one type of material through angles varied in relation to thegroups of increments to insure a regular helical arrangement of saidcoarser portions of said one type of material.

4. In combination, a blast furnace having a distributor hopper includinga small bell, a large bell in series with said small bell, motive meansfor rotating said distributor hopper, control means for insuring thatthe amplitude of such rotary movement is a definite angular increment ora multiple thereof, and other control means fining the number of suchangular increments comprislng'each of such rotary'movements.

5. In combination, a blast furnace having a distributor hopper includinga small bell. a large bell in series with said small'bell, motive meansfor rotating said distributor hopper, control means for insuring thatthe amplitude of such rotary movement is a definite angular increment ora multiple thereof, other control means for defining the number of suchangular increments comprising each of such rotary movements, and meansresponsive to movement of said large bell for governing the amplitudesof such rotary movemen 6. In combination, a blast furnace having adistributor hopper including a small bell, a large bell in series withsaid small bell, motive means for rotating said distributor hopper, acontroller switch driven from said distributor hopper, said controllerswitch being adapted to stop said motive means at definite regions inthe rotation of said distributor hopper, a second controller switch forcontrolling the amplitudes of the rotations of said distributor hopper,and a third controller switch responsive to the positions of said smallbell and said distributor hopper for controlling said second controllerswitch.

7. In combination, a blast furnace having a distributor hopper includinga small bell, a large bell in series with said small bell, motive meansfor rotating said distributor hopper, skip hoist mechanism fordelivering material to said distributor hopper, switch mechanism forcontrolling operation of said small bell and said skip hoist mechanism,a controller switch for stopping the rotation of said distributor hopperat definite regions, andmeans responsive to said large bell fordetermining the amplitudes of rotation of said distributor hopper, saidswitch mechanism being responsive to the positions of said hoistmechanism and said large bell.

8. In combination, a blast furnace having a distributor hopper includinga small bell, a large bell in series with said small bell, motive meansfor rotating said distributor hopper, skip hoist mechanism fordelivering material to said hopper, a controller switch responsive tooperations of said large bell for insuring definite angular positions ofsaid distributor hopper, and timing means responsive to said controllerswitch for determining the amplitudes of rotation of said distributorhopper.

9. In combination, a blast furnace having a distributor hopper includinga small bell, and a large bell in series with said small bell, means forrotating said hopper, control means for said rotating means for insuringthat said hopper will stop at the end of certain predeterminedincrements of rotation, said control means being responsive to movementsof said large bell.

10. In combination, a blast furnace having a distributor hopperincluding a small bell, a large bell in series with said small bell,means for rotating said hopper, a controller switch responsive tomovements of said large bell for determining the angularity of rotationof said hopper, and means responsive to opening movements of said smallbell for returning said controller switch to initial position.

11. In combination, a blast furnace having a distributor hopperincluding a small bell, a large bell in series with said small bell,motive means for rotating said distributor hopper, skip hoist mechanismfor delivering material to said hopper, switch mechanism responsive tooperations of said large bell for insuring definite angular positions ofsaid distributor hopper, and means cooperating with said switchmechanismlor'delaving the operation of said skip hoist mechanism when necessaryto insure that the desired rotation of said hopper and the operation ofsaid small bell is completed before said skip mechanism delivers a skiptub to a position permitting materials to be discharged therefrom.

12. In combination, a blast furnace having a distributor hopperincluding a small bell and a large bell in series with said'emall bell,means for rotating said hopper, control means for said rotating meansfor insuring that said hopper will stop at the end of certainpredetermined increments of rotation, skip hoist mechanism, governingmeansfor delaying the initiation of operation of said skip hoistmechanism under predetermined conditions, dependent upon the amount ofrotation required of said hopper.

13. In combination, ablast furnace having a distributor hopper includinga small bell and a large bell in series with said small bell, means forrotating said hopper, control means for said rotating means for insuringthat said hopper will stop at the end of certain predeterminedincrements of rotation, skip hoist mechanism, governing means forpreventing the initiation of operation of said skip hoist mechanismexcept under predetermined conditions, and means cooperating with saidcontrol means for defining said predetermined conditions, said controlmeans being responsive to movements of said large bell.

14. In combination, a blast furnace having a distributor hopperincluding a small bell, a large bell in series with said small bell,motive means for rotating said hopper, controlmeans for said motivemeans responsive to movements of saidlarge bell for insuring thepositioning of said hopper at definite angular positions, a secondcontrol means for said motive means for determining the amplitudes ofrotation of said hopper, skip hoist mechanism, and governing means forcontrolling the initiation of movement of said skip hoist mechanism,said governing means being responsive to said second control means.

15. In combination, a blast furnace having a distributor hopperincluding a small bell, a large bell in series with said small bell,means for rotating said hopper, a controller switch responsive tomovements of said large bell for determining the angularity of rotationof said hopper, skip hoist mechanism, and governing means for delayingthe initiation of movement of said skip hoist mechanism depending uponthe amount of rotation required of said hopper, said governing meansbeing responsive to said controller switch.

16. In combination, a blast furnace having a distributor hopperincluding a small bell, alarge bell in series with said small bell,means for r0- tating said hopper, means responsive to movements of saidlarge bell for determining the angularity of rotation of said hopper,skip hoist mechanism, and means for delaying the initiation of movementof said skip hoist mechanism in response to said angularity determiningmeans.

ARTHUR J. WHITCOMB. GORDON FOX.

